Background Hemostasis and repair are two essential processes in wound healing, yet early hemostasis and following vascularization are challenging to address in an integrated manner. Results In this study, we constructed a hemostatic sponge OBNC-DFO by fermentation of Komagataeibacterxylinus combined with TEMPO oxidation to obtain oxidized bacterial nanocellulose (OBNC). Then angiogenetic drug desferrioxamine (DFO) was grafted through an amide bond, and it promoted clot formation and activated coagulation reaction by rapid blood absorption due to the high total pore area (approximately 42.429 m2/g measured by BET). The further release of DFO stimulated the secretion of HIF-1α and the reconstruction of blood flow, thus achieving rapid hemostasis and vascularization in damaged tissue. This new hemostatic sponge can absorb water at a rate of approximate 1.70 g/s, rapidly enhancing clot formation in the early stage of hemostasis. In vitro and in vivo coagulation experiments (in rat tail amputation model and liver trauma model) demonstrated superior pro-coagulation effects of OBNC and OBNC-DFO to clinically used collagen hemostatic sponges (COL). They promoted aggregation and activation of red blood cells and platelets with shorter whole blood clotting time, more robust activation of endogenous coagulation pathways and less blood loss. In vitro cellular assays showed that OBNC-DFO prevailed over OBNC by promoting the proliferation of human umbilical vein endothelial cells (HUVECs). In addition, the release of DFO enhanced the secretion of HIF-1α, further strengthening vascularization in damaged skin. In the rat skin injury model, 28 days after being treated with OBNC-DFO, skin appendages (e.g., hair follicles) became more intact, indicating the achievement of structural and functional regeneration of the skin. Conclusion This hemostatic and vascularization-promoting oxidized bacterial nanocellulose hemostatic sponge, which rapidly activates coagulation pathways and enables skin regeneration, is a highly promising hemostatic and pro-regenerative repair biomaterial. Graphical Abstract

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Total focusing method (TFM) based on full-matrix capture (FMC) is widely used in the field of nondestructive testing due to its high resolution and high signal-to-noise ratio. In order to solve the problems of the slow speed of traditional time-domain total focusing imaging and poor imaging quality, this paper proposes a total focusing imaging method weighted by circular statistics vector (CSV) in the Fourier domain (FD). Firstly, the cosine and sinusoidal components of the instantaneous phase in the undelayed RF signal are extracted, and the coherence factor is established according to the cosine and sinusoidal components in the FD domain. Finally, the total focusing image in the FD domain is weighted. The complexity calculation shows that CSV-weighted imaging in the FD domain has a higher imaging speed than delay-and-sum (DAS) imaging. The DAS total focusing imaging algorithm, FD domain total focusing imaging algorithm, and FD domain CSV weighted imaging algorithm are used to verify the hole and crack defects in brass test blocks, aluminum test blocks, and steel test blocks. The experimental results show that the proposed FD domain CSV weighted imaging map generally shows higher resolution and signal-to-noise ratio, and the algorithm has higher robustness. Also, it has revealed a low computational load.

Immersion ultrasonic phased array imaging technology offers great advantages, particularly in coupling and automatic detection of industrial non-destructive testing (NDT). To suppress the influence of secondary interface echoes in the immersion ultrasonic phased array imaging, a novel phase circular statistics vector (PCSV) weighting method is proposed in this paper. Firstly, the PCSV factor matrix is established according to the phase consistency of the echo signals. Secondly, due to the higher phase coherence of the defect echo, the PCSV factor matrix is used to weight the TFM image to suppress the secondary interface echo. The result shows the secondary interface echoes are effectively suppressed in the total focusing method (TFM) image on a 0~40 dB scale. It is also shown that PCSV weighting could not only suppress the secondary interface echoes but also improved the image quality in terms of SNR and lateral resolution by comparing with traditional TFM.